Transport basket and method of producing the same

ABSTRACT

A transport basket for raising personnel or material to elevated positions from a vehicle having an elevatable basket supporting structure thereon. The basket comprises a liner of electrical insulating material and an outer rigid jacket covering the exterior surface of the liner. A method of producing the transport basket involves molding the liner in a rotational mold without a core, removing the liner from the mold, and thereafter covering the exterior surface of the liner with glass fiberimpregnated plastic resin.

[5 6 References Cited UNITED STATES PATENTS 965Myers........................

Otto M. Mueller; Melvin R. Nordin, both of Lakeville, Minn. Appl. No.829,489 [22] Filed nited States Patent [72] lnventors 6Q636 MZMBM 200202oo oonoo t mm a a nc ram 3 n" GWT 888 666 999 mo 0 a h c 3 M m d l Wd lo .m & R 8 t 6pm eh m mw ABSTRACT: A transport basket for raisingpersonnel or 182/46 material to elevated positions from a vehicle havingan 182/2 182/222 220/83: elevatable basket supporting structure thereon.The basket comprises a liner of electrical insulating material and anouter rigid jacket covering the exterior surface of the liner. A 182/46method of producing the transport basket involves molding I the liner ina rotational mold without a core, removing th 182/2 220/83 liner fromthe mold, and thereafter covering the exterior surface of the liner withglass fiber-impregnated plastic resin.

Lakeville, Minn.

[54] TRANSPORT BASKET AND METHOD OF PRODUCING THE SAME 2 Claims, 6Drawing Figs.

[51] Int. [50] Field of PATENTED DEC 7 an SHEET 1 of 2 .1! munINVENTOIE- 0770 M MUE'LL R BYMFLV/ 4 12. Noflouv HUO NEYS TRANSPORTBASKET AND METHOD OF PRODUCING THE SAME BACKGROUND OF THE INVENTIONTransport baskets for carrying workmen to elevated posi tions, fromvehicles, are known, particularly in the fields of street lightingmaintenance, and tree trimming, outdoor sign work, and others. Suchbaskets have been heretofore made from molded resins or glass fibers orglass cloth, for mechanical strength and savings in weight. For thepurpose of provid ing electrical insulation, as against possiblegrounding, for a workman occupying the basket, open-topped insulatingliners have been provided. Such liners, usually molded of materialhaving high dielectric strength, have been merely slipped into thebaskets after the baskets are finished. These molded liners are mostlysemirigid and usually have straight or upwardly diverging sidewalls toenable the same to be placed in the baskets. Some transport baskets haveundercut or downwardly diverging sides to provide adequate foot spacefor an occupant. Liners of the above-mentioned variety, placed therein,materially reduce foot space, and add to the instability of the occupantof the basket when reaching laterally outwardly therefrom. Moreover,such liners are easily removed, and use of a transport basket withoutthe liner often creates a hazard when used in connection with electricalapparatus.

SUMMARY OF THE INVENTION The transport basket of this invention involvesa molded liner of electrical insulating material, such as athermoplastic resin, and a rigid jacket of glass fiber-impregnatedresin. The liner is preferably formed by rotational casting or vacuumthermo forming to provide a bottom wall, a peripheral wall, and an opentop, the jacket being applied in fluid form to the outer surfaces of theliner bottom and peripheral walls after removal of the liner from themold, and cured to a substantially rigid state. The basket is generallyrectangular in shape, the peripheral wall including generally flat frontand rear walls and sidewalls, the front and sidewalls having laterallyoutwardly offset portions adjacent the bottom wall defining an inwardlyopening recess for the feet of the occupant. One of the walls of thebasket is formed to provide a second laterally outwardly projectinghollow step portion defining an inwardly opening recess above the levelof the above-mentioned recess, to aid the occupant in entering andleaving the basket.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a view in perspective, as seenfrom the top, front and one side, of a transport basket produced inaccordance with this invention;

FIG. 2 is a view in rear elevation, on a reduced scale;

FIG. 3 is an enlarged fragmentary section taken on the line 3-3 of FIG.2;

FIG. 4 is a vertical section taken on the line 4-4 of FIG. 2;

FIG. 5 is a view in perspective of a rotational mold for producing theliner section of the transport basket; and

FIG. 6 is a view in perspective of the liner section, illustrat ing astep in the method of producing the completed transport basket.

DETAILED DESCRIPTION The transport basket of this invention isopen-topped, and may be made in any desired shape, such as generallycylindrical or rectangular. For the purpose of the present example, thebasket is shown as being generally rectangular, and comprises a linersection 1 of material having high electrical insulating characteristics,such as polyethylene or other suitable material which may be easilymolded; and a rigid outer casing or jacket of other material, such asglass fiber-impregnated resin. The liner section I is formed to providea generally horizontally disposed flat bottom wall 2, generallyvertically disposed front and rear walls 3 and 4 respectively, andlaterally disposed generally vertical sidewalls 5. The open top of theliner 1 is encompassed by a horizontally disposed marginal flange 6. Therear wall 4 of the liner 1 is formed to provide a pair of laterallyspaced generally vertical reinforcing ribs 7, see particularly FIGS. 3and 6. The front and sidewalls 3 and 5 respectively are formed toprovide laterally outwardly offset portions 8 which define a laterallyinwardly opening recess 9 that extends continuously about the side andfront walls of the liner 1, the opposite ends of the recess beingdefined by the rear wall 4 adjacent the bottom wall 2. The front wall 3intermediate the recess 9 and top marginal flange 6 is further formedwith a laterally outwardly projected or ofiset portion of generallyrectangular form, having top and bottom wall portions 10 and 11respectively, a front wall portion 12, and opposite sidewall portions13, the wall portions defining a laterally inwardly opening recess 14 inupwardly spaced relation to the underlying portion of the recess 9. Asshown, the upper end portions of the front and sidewalls 4 and 5respectively are formed to provide laterally outwardly offset portions15 adjacent the marginal flange 6 to impart rigidity to the liner 1adjacent the open upper end thereof.

The outer surface of the liner 1 is covered by a rigid jacket 16preferably made from glass fiber-impregnated resin or similar materialhaving substantially greater mechanical strength and rigidity than thatof the liner 1. As shown, the jacket 16 covers the entire bottom, front,rear and sidewalls of the liner 1 including the undersurfaces of themarginal flange 6.

A vertically extending rib 17, of glass fiber-impregnated resin or othersuitable material, is mounted on the rear wall 4 intermediate the ribs 7thereof, and is covered by the jacket 16. An attachment member 18, bymeans of which the trans port basket is secured to a lifting boom orsimilar elevating mechanism, comprises a boss 18 projecting rearwardlyfrom the upper end portion of the rear wall 4, and an anchoring plate 19disposed in face-to-face engagement with the outer surface of the rearwall 4 and held thereagainst by the upper end portion of the rib 17, thejacket 16, and a short rib section 20 underlying the marginal flange 6and aligned with the rib 17. If desired, the anchoring plate 19 may besecured to the rear liner wall 4 by suitable adhesives, not shown. Inthe embodiment of the invention illustrated, the jacket 16 is cove redwith a relatively thin coat 21 of paint of insulating material such aspolyethylene or other thermoplastic material having high dielectricstrength.

The transport basket, being made primarily of synthetic plastic resin,is light in weight, requiring little power to elevate and manipulate thesame in use. The inwardly opening recess adjacent the bottom wall 2provides ample insulated space for the toe portions of the operatorsshoes, enabling the operator to stand more closely to the insulatedfront and sidewalls 3 and 5 and more comfortably lean thereagainst whenreaching outwardly from the basket to perform required activity at armslength. The outwardly projected portion of the front wall 1, definingthe recess 14, provides both an interior and an exterior step forassisting the user in entering or leaving the basket.

The producing of a transport basket of the general type above described,and including a liner of insulating material having recessed portionssuch as the recesses 9 and 14 therein, and by the usual fabricating ormolding processes, is difficult and highly expensive. Further as aboveindicated, baskets with removable liners are apt to be used withoutbenefit of the safety liners. In order to produce an inexpensive andlightweight basket of the required strength and insulating qualities, wehave developed the following method of producing the same without thenecessity of using molds having complex core structures. In one methodof producing the present transport basket, the liner 1 is formed byintroducing a charge of thermoplastic material, such as polyethyleneinto a split hollow mold of the type illustrated in FIG. 5 and indicatedat 22. The mold 22 is devoid of a core and is mounted for rotation on atransverse axis within a frame 23 which in turn is provided withtrunnions or the like 24 disposed on an axis transversely of the axis ofrotation of the mold 22. The mold 22 is heated to the meltingtemperature of the charge of thermoplastic material therein and rotatedon the axis of its mounting to the frame 23, while the frame 23 isrotated on the axis of the trunnions 24, the process being well known asrotational casting. As the heated mold 22 is thus rotated on two axes,the melted charge of liner material coats the inner surface of the moldto a uniform thickness, after which the mold is cooled, the moldsections separated, and the liner I removed therefrom. The attachmentmember 18 and central rib 17 are then adhered to the rear wall 4, andthe liner I placed on a suitable support 25 in an inverted condition,see FIG. 6. With the exception of the top surface of the marginal flange6, the entire outer surface of the liner 1 is then covered to a desiredthickness with glass fiber-impregnated resin, such as a polyester orepoxy resin, and the same permitted to cure to a hardened solid state.In FIG. 6, the glass fiber and resin mixture is shown as being sprayedon the outer surface of the liner 1 by means of a conventional spraynozzle 26. Optionally, the jacket 16 may be produced by applyingalternate layers of resin and woven glass cloth to the exterior surfaceof the liner 1 until a jacket 16 of desired thickness is achieved. Afterthe jacket 16 has thoroughly cured, the outer surface thereof may becoated with a layer 21 of plastic insulating material. such aspolyethylene. or other high dielectric thermoplastic material, ifdesired.

It will be appreciated that the safety liner can be produced in otherways, such as by thermo forming, centrifugally cast, or by blow molding.

The above-described method of producing a transport basket is relativelysimple and inexpensive, and produces a basket that is light in weightand of substantial dielectric and mechanical strength, and which may beeasily entered and as easily vacated. The liner 1 is securely anchoredwithin the jacket, and due to the larger area at the bottom thereof thanat its open top, removal thereof from the jacket may be accomplishedonly with extreme difficulty. As a matter of fact, producing a liner asabove described eliminates the necessity for removing the liner from thejacket.

What is claimed is:

l. A transport basket comprising:

a. an open topped, generally rectangular liner of molded electricalinsulating material having a generally flat bottom wall, and aperipheral wall including generally vertically disposed front, rear andsidewall elements; said peripheral wall including a laterally outwardlyoffset portion adjacent said bottom wall, said offset portioncooperating with said bottom wall to define a laterally inwardly openingrecess;

c. a rigid jacket of glass fiber-impregnated resin covering the exteriorsurface only of said bottom and peripheral walls of the liner;

d. and an attachment member projecting rearwardly from said rear wallelement and including an enlarged anchoring portion parallel to saidrear wall element and disposed between said liner and jacket andanchored therebetween.

2. The transport basket defined in claim 1 in which said front andsidewalls each include said outwardly offset portion, said recessextending continuously about the sides and front of said basket andhaving opposite ends adjacent said rear wall.

1. A transport basket comprising: a. an open topped, generallyrectangular liner of molded electrical insulating material having agenerally flat bottom wall, and a peripheral wall including generallyvertically disposed front, rear and sidewall elements; b. saidperipheral wall including a laterally outwardly offset portion adjacentsaid bottom wall, said offset portion cooperating with said bottom wallto define a laterally inwaRdly opening recess; c. a rigid jacket ofglass fiber-impregnated resin covering the exterior surface only of saidbottom and peripheral walls of the liner; d. and an attachment memberprojecting rearwardly from said rear wall element and including anenlarged anchoring portion parallel to said rear wall element anddisposed between said liner and jacket and anchored therebetween.
 2. Thetransport basket defined in claim 1 in which said front and sidewallseach include said outwardly offset portion, said recess extendingcontinuously about the sides and front of said basket and havingopposite ends adjacent said rear wall.